Electrical crystal unit



w J!!! n- N w m m 4 T T 2 m n M r 4 Ma A 6 1 2, @M S V. M M 0.

Filed Aug. 25, 1948 C J RYAN ELECTRICAL, CRYSTAL UNIT June 16, 1953 Patented June 16, 1953 2,642,486 ELEoTRicAL CRYSTAL UNIT Charles J. Ryan, Medford, Mass., assignor to Sylvania Electric Products Inc.', Salem, Mas's'.,fa corporation of Massachusetts Application August 25, 1948, Serial N0. 46,043

4 Claims. 1

This invention relates to semi-conductor crystal units and the like, for example crystal rectifiers, amplifiers, oscillators and similar devices. The present application discloses features that are also claimed in copending application Serial No. 74,768, filed February 5, 1948, by Ralph B. Collins, Jr. and assigned to the assignee hereof.

An object of the invention is the achievement of a small, compact, inexpensive crystal unit of improved electrical characteristics.

A feature of the invention is the enclosure of the crystal in a glass tube sealed at its ends by metal contact pieces extending therethrough.

Other features, objects and advantages of the invention will be apparent from the followin specification taken in conjunction with the attached drawings in which:

Fig. l is a profile section of a device according to the invention.

Fig. 2 is a similar View of a portion of the device with a tool in place for adjustment.

In the figures, the glass tube I, has sealed to each of its ends a metal sleeve 3, 4, the sleeve 4 having a so-called bead or circumferential depression 5, that is a region where the diameter of the cylinder is smaller than in the remainder of the cylinder 4. The inside end of cylinder 4 is closed by a metal plug 6 to which the catwhisker contact I is alfixed. This catwhisker '1 may be, for example, as shown in copending application Serial No. 492,163 of E. T. Casellini, and has the pointed end 8 in contact with the flat surface 9 of crystal H), which may be for example of germanium containing a small amount of an impurity, for example tin, to have semi-conducting characteristics. The crystal may be soldered or otherwise afiixed to the metal plug H which closes the inner end of sleeve 3. The metal sleeves 3, 4, should be of metal which can be sealed effectively to the glass used, Kovar being satisfactory for hard glass, for example. The glass tube I may have a slightly reduced inner diam-eter near its ends, forming the rims I2, [3. Pigtail connecting wires [4, I5 may be attached to the outer ends of sleeves 3, 4, for convenience. The rims l2, [3 should be far enough removed from the crystal 9 to avoid overheating it during the sealing operation.

Fig. 2 shows the catwhisker just out of contact with crystal 9, which is the position it will ordinarily have just after the sealing of rims [2, I3 to sleeves 3, 4. A spacing plunger It may then be forced into sleeve 4 and against the inside surface of lead 5 to force the catwhisker point 8 against the crystal surface 9 with a desired pressure. The catwhisker contact 8 can be guided against various points on the crystal surface 9, in case the final point does not give satisfactory characteristics, by pushing the plunger, which is of somewhat smaller diameter than the inside of sleeve 4, against one side of the bead or the other. A similar head could, of course, be used on the other sleeve 3, if :desired.

The sealed tube 1 may be filled with air at ordinary atmospheric pressure, or evacuated, or filled with an inert or non-deleterious gas, such as nitrogen or one of the rare gases.

If the plug 6 is made of insulating material, for example plastic, two or more catwhiskers may be used in the manner now known in the art to allow the crystal unit to act as an amplifier. One or more of the catwhiskers would then be for control purposes, and one or more for output purposes. Of course, plug 6 could be metal, and the catwhiskers insulated from it by bushings or the like where necessary.

What I claim is:

l. A semi-conductor crystal unit comprising a tubular glass envelope, a metal sleeve sealed at one end thereof to close off the same, a semiconductor crystal attached to said sleeve, a beaded metal sleeve sealed to the other end of said envelope to close off the same, and a catwhisker contact for said crystal attached to said beaded sleeve and capable of adjustment by deformation of the sleeve where beaded.

2. A semi-conductor crystal unit comprising an enclosing envelope, a pair of diode elements contained within said envelope in mutual contact and a sleeve having a closed inner end supporting one of said elements in contact with the other, said sleeve having an externally accessible radially extending circumferential corrugation which may be deformed to vary the length of the sleeve.

3. A semi-conductor crystal unit comprising a tubular glass envelope, metal sleeves extending into said envelope and sealed to said envelope at an intermediate point of each sleeve, the innermost ends of said sleeves being closed off, a pair of translator elements in mutual engagement Within said envelope, said elements being carried by the innermost ends of the closed-off sleeves, respectively, one of said sleeves having a bead extending circumferentially about and radially inward at a point along the sleeve within the envelope said bead being accessible for adjustment from the outside and being deformable to vary the length of the sleeves.

4. A semi-conductor unit comprising a tubular mutual contact within said envelope by said members, respectively, said elements including a semi-conductor element and a contact element, one of said members being tubular and having a closed end within the envelope carrying said semi-conductor element, said closed end being separated by a substantial distance from the glass-to-metal seal of said tubular member, and

the end of said tubular member opposite said closed end being open.

CHARLES J. RYAN.

References Cited in the file of this patent UNITED STATES PATENTS Number D. 156,501- 756,676 1,741,319 2,145,542 2,360,701 2,414,137 2,438,110

Name 7 Date Gates Dec. 20, 1949 Midgley Apr. 5, 1904 Lazarus Dec. 31, 1929 Swanson Apr. 18, 1939 MacFadden Oct. 1'7, 1944 Branson Jan. 14, 1947 Brattain Mar. 23, 1948 

